Method of and apparatus for finishing glassine paper



P. w. BIDWELL 1,739,572

NISHING GLASSINE PAPER Dec. 17, 1929.

METHOD OF AND APPARATUS FOR FI Filed Sept. 19- 1927 INVENTOR.

BY %M ATTORNEYS.

pressure uniformly to Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE PAUL w. nmwnnn,

son, me, or HOLYOKE,

OF HOLYOKE, MASSACHUSETTS,

MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS ASSIGNOR TO B. I. PERKINS 80 Application filed September 1 This invention relates to improvements in the methods of and apparatus for finishing paper and is directed particularl ods of and apparatus for finis mg thin; highly polished and transparent paper such as glassine paper.

According to one well known method of finishing ordinary paper, it is passed between pairs of heavy metal rolls which are arranged to exert a considerable pressure to the paper and according to the particular paper being finished or the particular finish desired the rolls may be heated. The amount of pressure, heat and speed of the rolls is ordinarily variable so that the method and apparatus may be sufficiently flexible to provide a wide range of finishes to various kinds or rades of paper.

lassine paper has peculiar characterlstics so that it may be used for particular purposes and is thin and transparent as compared with ordinary papers and has 'a high gloss. Before the finishing operation, this paper resembles tissue paper in that it is thin and to attain the required transparency and high gloss, it must be subjected to heavy pressure uniformly applied thereto throughout its width as well as considerable heat, these being the important factors which produce the effect or finish which is characteristic of this grade or kind of paper.

The method and apparatus previouslydescribed is not adapted to produce the quality of paper to meet the present qu'irements, and is objectionable for the following reasons. It is impossible to finish the rolling surface or a pair of metal rolls so that they are exactly true or even sufliciently true as to be capable of exerting an even the paper throughout its width and the result is that the paper finished thereby is not uniformly transparent but has blotches or spots which are less to meth- -to the end that the surface of day exacting re- 9, 1927. Serial No. 220,512.

transparent and more opaque than the unblotched portion of the paper.

Accordlngto one novel vention, I provide a method whichconsists in finishing glassine aper b means of a pair of rolls which ave ro ling surfaces adapted to conform with one another and is accomplished by providing a metal roll which has a substantially hard rigid surface, while the other may be of a fibrous or yieldable material so as to have a relatively resilient or yieldable surface as compared with the other, the latter may conform to any unevenness of the surface of the former in their rolling contact so that a uniform even pressure is applied across the paper as is desirable and necessary.

According to another novel feature of the invention, the metal roll may be heated as is usual or desired to facilitate the finishing operation, while the other roll which absorbs heat and therefore is subject to deterioration is interiorly cooled to overcome the action of the heat to the end that a pair of rolls is substantially opaque so that in order P rovided which will have the long life desired and at the same time possess the ability to exert the even pressure and apply heat necessary for producing the desired hard, imzoth finish and give the transparent ef- The invention may be practiced in various ways but in order to illustrate the novel features thereof in the form atpresent preferred reference will be made to the accompanying drawi in which:

tion of an apparatus embodying the novel features of my invention by the means of which the method of my invention may be practiced.

Referring to the drawing in detail, 1 and 2 represent portions of the end frames or standards of a typical calender, which may be arranged in fixed spaced relation so as to be adapted to guide the journal boxes of a plu- The gure is a diagrammatic representa- I feature of my inrality of rolls in stacked relation one above the other. In the drawing, a single pair of rolls 3 and 4 is shown, but it will be understood that Other pairs may be located adjacent thereto if it is desired in finishing paper that the paper pass between more than one palr.

The roll 3 is preferably of metal and is of course machined on its periphery so as to have as far as possible a smooth even surface throughout its length. The m'etal employed for the roll will be preferably such as Will provide a substantially rigid and hard surface;

The roll 4 is preferably formed of some non-rigid material as distinguished from the metal roll just described and may be of a fibrous nature such as cotton, stalks or the like. The roll body is preferably formed by binding or clamping a plurality or stack of discs or laminations of suitable material between metallic binders or headers 5 which may be held in clamping relation on a hollow shaft or arbor 6 by means of locking collars 7. The particular form of construction is not important for the practice of the invention, except in so far as the characteristics of the body of the roll are concerned and I make mention of cotton laminations because I have found it possible by applying pressure to the ends of a stack of cotton laminations and the like to force them together to thereby provide a substantially firm and solid unified body portion. The laminations are machined to provide a smooth even rolling surface to the roll similar to the surface of the roll 3 against which it acts. By providing the roll 3 with a hard, smooth and substantially rigid surface and a smooth but less hard or relatively yieldable or resilient surface to the roll 4, it will be obvious that when in rolling contact the surface of the roll 4 will tend to conform to any unevenness of that of the roll 3 so that in efl'ect there will be an even uniform pressure applied throughout the width of paper passing through the bight of the rolls, as distinguished from a non-uniform pressure where rolls are employed which have equally rigid surfaces.

The roll 3 is preferably heated to some degree depending upon conditions and this may be accomplished by providing an opening therethrough so that steam or any heating medium may be introduced at one end, as by a pipe 10 and conducted therefrom as by a pipe 11.

The roll may be heated, of course, to any desired or required degree and where a plurality of pairs of rolls are employed, those rolls corresponding to the heated metal roll 3 may be connected by suitable piping with some convenient means for supplying the heating medium.

To provide the proper degree of transparmay and gloss to of the metal roll.

glassine paper, some degree as well as is some degree will be apparent that both may be controlled so as to of heat is necessary of pressure, and it heat and pressure obtain the desired tain amount or degree of pressure and vice V61 S3,.

Heat radiated by the roll 3 is absorbed by the metal parts of the roll 4 so that the body of the roll 4 becomes heated, which tends to char the laminations comprising the roll body, particularly in the vicinity of the central metal arbor and at the ends adjacent. the members As the material becomes charred, there is a tendency for it to give way under pressure and results in the roll becoming uneven on its surface and thereby destroys the ability to conform to the surface To overcome this, it is preferred to introduce a cooling medium to the central hollow shaft which may be conducted thereto by a pipe connection 13 and a similar connection 14 for conducting the same from the roll.

By thus introducing a cooling medium, the temperature of the shaft may be controlled so that the heating tendency of the roll 3 is overcome. It is not intended to cool the roll 4 so that it will affect the temperature of the roll 3 but rather it is desired to control the temperature of the roll 4 to such an extent that the heat of roll 3 will not injuriously affect it. By thus controlling the temperature, the action of the ressure and heat for the finishing operation is not interfered with or in any way impaire As with the roll 3, of rolls are employed ber of rolls such as 4 nected together for the able cooling medium.

The particular form of connections of the rolls is not of vital importance but they of course will be such as will permit a free rotation of the rolls for the calendering or finishing operation.

From the foregoing it will be observed that I have provided a method and apparatus for finishing paper by means of a pair of rolls which are constructed and arranged so that one has a substantially rigid surface while the other has a relatively yieldable surface, whereby I am able to attain an even uniform pressing contact while heat is applied to one roll to facilitate the finishing of the paper; the deteriorating effect of the heat to the other is overcome by cooling or controlling the temperature thereof without in any way interfering with the heat required for the finishing operation.

I am aware that many changes may be made in the form of the invention without departing from the scope thereof, and I prefer therefore to be limited if at all by the appended claim rather than by the foregoing description.

if a plurality of pairs as in a stack, a nummay be suitably eoncirculation of a suitamount of heat for a. cer- What I claim is:

An apparatus for making glassine paper b finis ing substantially opaque paperso t at it becomes transparent and has apolished surface comprislng, a pair of supports and a pair of ooacting pressure rolls )ournalled therein, one of said rolls including a substantially rigid hollow metal body for receivin aheatin medium, the other including a ho low meta shaft for receiving a cooling medium and a plurality of lamlnations of fibrous material held in a pressed together relation thereon to form a su stantially nonrigid body and provide a gieldable surface to conform to at of sai metal roll.

In testimony whereof I have afiixed my signature.

PAUL W. BIDWELL. 

